Penn Astronomers Will Use Newly Funded Telescope in Hunt for Dark Energy

After more than a decade of development and planning, the National Science Foundation has approved federal construction of the Large Synoptic Survey Telescope. The Association of Universities for Research in Astronomy, of which the University of Pennsylvania is a member, will manage the $473 million construction project.

The LSST will be constructed atop Cerro Pachón, a mountain in Chile’s Atacama Desert, one of the highest, driest locations in the world. It will see first light in 2019 and begin full science operations in 2022.

Gravitational lensing involves measuring minute distortions in the light of distant galaxies as a way of inferring the properties of objects that light passes by on its way to Earth. These objects include galaxies and cosmic superclusters, which are dominated by dark matter, a form of matter that is not directly visible. Lensing is also one of the main methods Bernstein, Jain and Jarvis are applying with the ongoing Dark Energy Survey. This survey is designed to explore dark matter as well as dark energy, the mysterious force that may be responsible for the accelerating expansion of the universe.

The LSST’s mission will expand upon the Dark Energy Survey’s capabilities, imaging about 10 times as many galaxies, each in greater detail.

“LSST will be able to detect galaxies two to three times further than the Dark Energy Survey telescope,” Jain said, “and it will cover about four times as much sky. Over the LSST’s 10-year survey, it will take about 800 exposures of each of 3 billion galaxies. With this detailed information on galaxies most of the way to the edge of the observable universe, we will carry out a wide range of cosmological studies.”

“One of the other advantages of the LSST,” Bernstein said, “is that it is a ‘time domain’ survey. It will catch the variability of stars, environments of black holes, supernovae, asteroids — all kinds of objects from inside the solar system to distant galaxies — over timescales that range from a few hours to a year.”

The data collected by the survey — a petabyte-scale database of astronomical images — will be made publically available in an effort to promote open research as well as science, technology, engineering and mathematics education.

Though federal funding has just now been approved, fabrication of the major mirror components for LSST is already underway, thanks to private funding received from the Charles and Lisa Simonyi Foundation for Arts and Sciences and Bill Gates and other individuals. Receipt of federal construction funds allows major contracts to move forward, including those to build the telescope mount assembly, the figuring of the secondary mirror, the summit facility construction, the focal plane sensors and the camera lenses.

"This agreement,” said Victor Krabbendam, LSST ‘s project manager, “is a tribute to the hard work of an exceptional team of highly skilled individuals, many of whom have dedicated more than a decade to bringing LSST to this point. After a rigorous design and development phase, the project team is ready to get down and dirty and actually build this amazing facility."

The LSST Camera fabrication budget, funded by the Department of Energy, will be settled later this year but is estimated at $165 million. Operations costs are estimated at $37 million per year for the 10-year survey.

LSST’s construction funding will be provided through NSF’s Major Research Equipment and Facilities account. LSST passed its NSF Final Design Review in December, and the National Science Board gave the NSF conditional approval to move the project to construction status in May. On the DOE side, LSST received Critical Decision-1 approval in 2011 and also just received CD-3a approval, which allows the project to move forward with long-lead procurements, in this case, the CCD sensors. The CD-2 review will take place the first week in November, with approval expected shortly afterward, formally fixing the baseline budget for completion of the camera project. The Particle Physics Project Prioritization Panel, an advisory subpanel of the High Energy Physics Advisory Panel, recommended last month that DOE move forward with LSST under all budget scenarios, even the most pessimistic.

LSST project activities are supported through a partnership between the National Science Foundation and the Department of Energy. The NSF supports LSST through a cooperative agreement managed by AURA. The Department of Energy-funded effort is managed by the SLAC National Accelerator Laboratory. Additional LSST funding comes from private donations, grants to universities and in-kind support from institutional members of the LSST Corporation, a non-profit entity with headquarters in Tucson, Ariz.

A computer rendering of the Large Synoptic Survey Telescope (Credit: LSST)

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